title: The initial tangent of the aortic pressure increase is an estimate of left ventricular contractility in pigs.
abstract: The aim was, to identify an estimate of left ventricular contractility derived from the aortic pressure wave without load changing manoeuvres. For this purpose, left ventricular contractility was assessed with several aortic pressure wave form derived parameters and was compared to standard parameters of left ventricular contractility (conductance technique) in an experimental study. Measurements were taken during baseline, after beta-stimulation and after injection of a beta-antagonist. The initial and the secondary tangent, the area under the aortic pressure, and the stroke volume were correlated with the endsystolic elastance, a mainly load independent measure of left ventricular contractility: The initial tangent of the aortic pressure increase correlated significantly with the endsystolic elastance (r = 0.54, P < 0.05). The initial tangent of the aortic pressure increase was significantly increased from baseline at beta-stimulation (from 20.2 +/- 4.7 to 36.4 +/- 6.8 mmHg s(-1), P < 0.05) and decreased after injection of a beta-antagonist (from 20.2 +/- 4.7 to 12.3 +/- 2.0, P < 0.05). Thus, we conclude that the initial tangent of the aortic pressure increase is a valid estimate of left ventricular contractility in piglets.
authors.affiliation: Clinic of Anesthesiology, Ludwig Maximilian University, Munich, Germany. Hille.Kisch-Wedel@med.uni-muenchen.de
authors.forename: Hille
authors.initials: H
authors.lastname: Kisch-Wedel
authors.forename: Gregor
authors.initials: G
authors.lastname: Kemming
authors.forename: Franz
authors.initials: F
authors.lastname: Meisner
authors.forename: Michael
authors.initials: M
authors.lastname: Flondor
authors.forename: Sebastian
authors.initials: S
authors.lastname: Bruhn
authors.forename: Carolina
authors.initials: C
authors.lastname: Koehler
authors.forename: Bernhard
authors.initials: B
authors.lastname: Zwissler
mesh_terms: D000818:Animals; D001011:Aorta / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology*; D003198:Computer Simulation; D008955:Models, Cardiovascular; D009200:Myocardial Contraction / Q000502:physiology*; D013552:Swine; D016277:Ventricular Function, Left / Q000502:physiology*